Student’s Guide
Galilei 27 Orbiting Iris 2 (Part 1)
Camil Cyr
Collège de Maisonneuve
Adaptation: Caroline Viger
John Abbott College
Galilei 27 Orbiting Iris 2 (Part 1)
Context
Within the scope of the EESP project (Exploration of Extrasolar Planets), we have identified three planets
that are suitable for sustaining life forms that are similar to us. We are in the process of developing
various mission scenarios that could eventually be carried out on these three planets. You have been
selected to plan the encounter between Galilei 27 and Iris 2.
Galilei 27 is the name of the space ship that will transport the astronauts. Iris 2 is the name of the planet,
among the suitable three, that is closest to Earth. Planet Iris 2 has a lower mass than that of the Earth but
has a smaller radius. This is the information we have gathered so far:
Mass of Iris 2: mI = 2 · 1024 kg
Radius of Iris 2: rI = 2 000 km
Mass of Galilei 27: mG = 5 · 105 kg
Your task is to calculate certain parameters that will be needed to accomplish the technical aspects of the
mission scenario. Perform the following calculations:
We should be able to approach Iris 2 without any problems. However, in order to land on its surface, we
must know the attractive force that will be exerted on the space ship when it is positioned at a distance of
10 000 km from the planet’s surface.
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Calculate the attractive force that will be exerted by Iris 2 on the space ship when it is
positioned at that distance from the surface of the planet.
Calculate the acceleration that Galilei 27 will experience at that distance.
Please note: this data will help us design a landing plan (the thrust the motors will need to help the
spaceship brake during its landing, the adequate quantity of fuel, the time it takes to brake, etc.)
In the probable event that Galilei 27 lands on Iris 2 as anticipated, physiological factors must also be
taken into account:
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Calculate the gravitational acceleration on the planet’s surface.
What force will the astronaut need to apply in order to hold a radiation monitor that has a
mass of 2 kg?
If the astronaut drops the monitor from a height of 1 metre, how long will it take for it to fall to
the ground?
Please note: these facts will allow us to evaluate how the human body will react to gravity on Iris 2. In
addition, they will help us choose the materials needed for the fabrication of space suits, and the technical
equipment that the astronauts will carry when they first walk on Iris 2. They will also enable us to
determine other parameters, such as resistance of the materials chosen.
PBL/Student’s Guide - Galilei 27 Orbiting Iris 2 (Part 1)
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Three-Step Cycle
List all the revelant information you have gathered from the problem. Based on this information,
state what you need to know to solve the problem. As new information comes in, you will want to
summarize and update the relevant information you have gathered and ask new questions.
List the Following:
What We Know
What We Need to Know
PBL/Student’s Guide - Galilei 27 Orbiting Iris 2 (Part 1)
Summary
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